Half to edward j



(No Model.)

B. P. PORTIN. SURFACE GAGE; No. 508,213.

Patented Nov. 7, 1893.

- WITNESSES UNITED STATES PATENT OFFICE.

BENJAMIN r. FORTIN, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR on ONE- HALF TO EDWARD J. DAVEYYOF SAME PLACE.

s u RFAC'E-GAG E.

SPECIFICATION forming part of Letters Patent'No. 508,213, dated November 7, 1893. Application filed March 3, 1893- I Serial No. 464.551. (No model.)

To all whom, it may concern: and screw to turn freelyinhead 9 but retains Be it known that I, BENJAMIN P. FoRTIN, a it against other than rotary movement. The citizen of theUnited States, residingat Bridgelower portion of the slide consists of a head port, in the county of Fairfield and State of 1 2 which has formed integral with it hub 5 5 Connecticut, have invented certain new and which carries the needle rod and also a hub useful Improvements in Surface-Verniers; 13 through which the standard passes and to andI do hereby declare the following to be a which it is locked. by a set screw 14. The full, clear, and exact description of the inthreaded lower end of the screw engages head vention, such as will enable others skilled in 12. I It follows therefore that when the screw [O the art to which it appertains to make and is rotated head 9 being locked in position, use the same. head 12 and the parts carried thereby will be My inventionhas for its object to produce moved up or down as may be required. an instrument which shall be especially 15 is a gage plate which is'secured to head adapted for use in connection with metal 12 and is provided with a scale adapted to 15 planers to indicate when the piece of metal register with scale 3.

that is being operated upon has been planed 15 is a plate secured to the needle rod and down to the proper thickness, it being desirprovided with a scale 17. At the outer end able in an instrument of this class to make ofthe rod is pivoted a needle 18 which is prothe capacity as great as possible, to provide vided at its outer end with an angle piece 19 7o 20 a quick and accurate adjustment to different which is the contact point of the instrument pieces of work, and furthermore that a scale with the piece of work upon which it is used. be provided which shallbegraduated so finely 2O denotes a spring one end of which is as to indicate Variation from the required coiled about or otherwise attached to the pivot thickness to the min utest fraction of an inch. 21 upon which the needle turns, the other end 25 With these ends in View I have devised the of said spring engaging a pin 22 which exnovel instrument which I will now describe tends outward from the needle, the outer end referring by numbers and letters to the acof the pin being preferablysplitand thespring companying drawings forming part of this inserted therein, the object of this spring bespecification in which ing to holdthe point of the needle at the zero 0 Figure 1 is a side elevation'of my novel point of scale 17.

surface Vernier; Fig. 2 an end elevation; Fig. In practice, I preferably make the distance 3 a plan view, and Fig. 4 isa section on the from the center of pivot 21 to the point of the line 00 0c in Fig. 2 looking down. angle piece and to the point of the needle as 1 denotes the base and 2 the standard ex- 1 to 8, so that any irregularity or extra thick- 3 5 tending upward therefrom and provided with ness of the piece of Work that is being opera flattened side having upon it a scale 3. ated upon sufficient to deflect the angle piece A denotes the slide as a'whole and 4 the to the slightest extent will produce eight times needle rod which is'carried thereby. This as great a deflection of the point of the nee,-

rod is provided with a fiat side and passes dle. Theinstrument is thus enabled to meas- 0 through a hub 5 at the lower end of the slide ure the most infinitesimal variations in thickin which it is locked after adjustment by a ness of the piece of work to which it is ap set screw 6. The upper portion of the slide plied. In use the standard rests upon the consists of a hub 7 through which the standbed of the planer.

ard passes and which is locked in position Supposethat the piece of work being oper- 5 5 after adjustment by a set screw 8. This hub ated upon 1s required to have an exact thickhas formed integral with it a head 9 having ness of three-fourths of an inch. Set screws a vertical openingthrough which the upper 8 and 14 are loosened and the slide is moved end of a screw 10 passes loosely, and a transby hand until the scale upon plate 16 regi verse slot in which lies a knurled finger piece ters with scale 3 to indicate the required 50 11 which is rigidly secured to the screw. thickness. Set screw8is then tightened up.

This construction permits the finger piece As this adjustment has been merely a hand IOO adjustment it is of course obvious that it is approximate only. Absolutely accurate adjustment is secured by rotation of screw 10 by means of the finger piece thereby raising or lowering hub 13 and the parts carried thereby as may be required, to cause the scale upon plate 15 to register accurately with'scale 3 upon the standard. Hub 13 is then looked in position by tightening up set screw 14. The special scale that is used upon plate 15 and the standard is of course not of the essence of my invention. It is common in scales of this class to graduate to twenty-five one thousands of an inch. After the piece of work'that is being operated upon has been planed down to approximately the required thickness the instrument is used by swinging the needle arm over the surface of the piece of metal, angle piece 19 being in contact therewith. If the surface of the piece is irregular or'if it is too thick the angle piece will of coursebe raised which will oscillate the needle on its pivot, the point of the needle indicating the superfluous thickness upon scale 17.

Owingto the fact that the point of the neodle describes an are eight times'greater than that-described by the angle pieceit is obvious that this instrument may be made to indicate as infinitesimally fine variations as can {possibly' be required in the very'finest work.

Having thus described my invention, I claim 1. The combination with the needle arm and suitable means for adjusting said arm vertically, of a needle pivoted to said arm and provided with an angle piece adapted to engage the piece of work upon-which'the instrument is used, the point of said needle describing a greater arc than that described by the angle piece so that the slightest movement of the angle piece will produce perceptible oscillation of the point of the needle.

2. The combination with the needle arm and suitable means for adjusting said arm vertically, of a needle turningon a pivot 21 on said arm and having a pin 22 and an angle piece adapted to engage the piece of work upon which the instrument is used, and a spring engaging the pivot and pin 22 whereby the needle is held at its normal position-until deflected by engagement of the angle piece with the piece of work upon which the instrument is used.

3. The combination with the needle arm havinga scale 17 and suitable means for-adjusting said arm vertically, of a needle pivoted to said arm and provided with an angle piece adapted to engage the piece of work upon whichthe instrument is used, and a spring acting to hold the point of the needle at the zero point of the scale until said needle is deflected by oscillation of the angle piece.

4. The combination with the standard and the slide having hub 5, and suitable means for adjusting said slide and looking it in position, of needle rod 4 engaging said hub and provided with a scale, a needle pivoted to said arm and having an angle piece adapted to engage the piece of work upon which the instrument is used, and a spring acting to hold the needleat the zero point of the scale until it is deflected by oscillation of the angle piece.

5. The combination with the needle arm having an angle pieceanda spring for holding said needle at its normal position, of the standard having ascale, the slide havinga scale adapted to registcr'therewith and suitable means for locking the slide'in position after adjustment.

6. The combination with the'needle arm,the needle having anangle piece, and a spring for holding the needle atits normal position, of the standard having a scale, and theslide consisting ofhub7l1avinga head 8, and a'set screw for locking said hub in position,-hub-l3 having ahead 12, a :hubo which carries the needle rod, screw 10 having a finger piece engaging head 9 thethrcadedportion of said screw engaging head 12 so that said headmay be raised or lowered relativelyto head 9, and a set screw forlocking hub 13 and the parts carried thereby in position after adjustment.

-7. The combinationwith the standard, hubs 7 and 15, and set screws for lockin g said hubs in position, of head 9 upon hub 7, head 12 and hub 5 carried by hub 18, screw 10 having a finger piece engaging head 9 and rotating therein but held against vertical movement, the lower end of said screw engaging head 12 whereby said head may be adjusted relatively to head 9, needle rod 4 engaging hub 5, a set screw forlocking said rod in position, and a needle pivoted to saidrod and provided with an angle piece adapted to engage the piece of work upon which theinstrument is used.

In testimony whereof 'I affix my signature in presence of two witnesses.

BENJAMIN P. FORTIN.

Witnesses:

A. M. Woos'rna, PEARL REYNOLDS. 

